Intraductal Papillary Mucinous Neoplasms (IPMNs) are group of cystic neoplasm that arise in the main pancreatic duct or its branches.
They are characterized by an intraductal proliferation of mucin-producing neoplastic cells arranged in papillary formations [1].
The gross appearance depends on which part of the pancreatic duct system is involved and the extent of the lesion [2,
3].
IPMNs can be morphologically distinguished in three groups: MD-IPMN (main duct IPMN),
BD-IPMN (Branch duct IPMN) and Combined IPMN,
involving both the main pancreatic duct and the branch ducts [3].
IPMNs are one of the most common cystic neoplasms of the pancreas representing 39% of cystic pancreatic neoplasms and 1-3% of exocrine pancreatic neoplasms.
Their real prevalence is not known yet.
In the last ten years,
IPMN is increasingly being recognized due to a combination of rising awareness of the disease,
increasing use of cross-sectional imaging and improved imaging techniques that are able to recognize smaller lesions than in the past [4-10].
IPMNs are typically observed in patients in their 6th-7th decade with a slightly higher incidence in females for BD-IPMN and in males for MD-IPMN [6-10].
Several studies have demonstrated that IPMNs can show a series of dysplastic changes from adenoma to invasive carcinoma and that different degrees of dysplasia can be found within the same lesion supporting the hypothesis of a progressive neoplastic lesion [1,
11].
The frequency of malignancy (carcinoma in- situ and invasive carcinoma) in main duct IPMNs is high,
ranging between 60% and 92% [12-17],
and significantly lower in branch duct IPMNs,
ranging from 6% to 46% [13,
14,
17-19].
The awareness of the risk of progression to malignancy,
combined with the increasing number of new diagnoses,
has led to the necessity to establish algorithms for the clinical management of these patients [20].
The first guidelines available were the Sendai consensus criteria,
published by the International Association of Pancreatology working group in 2006 and updated with the publication of the Fukuoka guidelines in 2012 [12,
21].
According to the Fukuoka consensus guidelines,
MD-IPMN is defined by a segmental or diffuse dilation of the MPD of >5 mm without other causes of obstruction.
BD-IPMN is characterized by pancreatic cysts with a diameter >5 mm that communicate with the MPD.
Combined IPMN meets the criteria for both MD-IPMN and BD-IPMN.
“High-risk stigmata” describe features associated with a high risk of malignancy and once detected the surgical resection is strictly recommended.
“High-risk stigmata” are: MPD diameter of ³10 mm,
the presence of an enhancing solid component and the presence of obstructive jaundice in a patient with a cystic lesion of the head of the pancreas.
“Worrisome features” describe features associated with a risk of malignancy,
but lower than for high risk stigmata.
When “worrisome features” are detected at MRI,
further investigations with EUS are recommended.
“Worrisome features” are: a dilation of the MPD of 5-9 mm,
a cyst diameter ≥30mm,
the presence of thickened enhancing cyst walls,
non-enhancing mural nodules,
an abrupt change in the MPD caliber with distal pancreatic atrophy and the presence of lymphadenopathy [21].
Fukuoka criteria are summarized in Table 1.
Fukuoka 2012 |
Criteria |
High-risk stigmata |
Obstructive jaundice |
|
Enhancing solid component |
|
MPD diameter ≥ 10 mm |
Worrisome features |
Cyst ≥ 30 mm |
|
MPD dilation of 5-9 mm |
|
Thickened enhancing cyst walls |
|
Non-enhancing mural nodules |
|
Abrupt change in the MPD caliber with distal atrophy |
|
Lymphadenopathy |
Purpose of this study is to assess the agreement between experienced readers working in referral institutions for pancreatic disease in different countries in recognizing the features defined by Fukuoka guidelines in a series of IPMNs.